Distributor mechanism



1959 E. c. M RAE 2,873,324

DISTRIBUTOR MECHANISM Filed April 24, 1956 E. C. Mc/PA E mmvrm ATTORNEYS United States Patent DISTRIBUTOR MECHANISM Edwin C. McRae, Dearborn, Mich., assignor to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Application April 24, 1956, Serial No. 580,316

2 'Claims. (Cl. 200-31) This invention relates to internal combustion engine ignition apparatus. It is specifically directed to the apparatus employed for repetitiously opening and closing the contact points which generate the high tension spark for the actual ignition of the fuel charge.

This invention has been perfected to enable such contacts to operate at very high speeds while propelled by a comparatively light spring pressure. This invention is further useful in that it permits a greater tolerance of manufacturing irregularities without interfering with the proper operation of the finished mechanism.

The mechanism is fully explained below in conjunction with the two figures of drawing in which- Figure 1 is a plan view of a distributor employing the invention, and

Figure 2 is a cross section of a portion of the apparatus taken on the line 2-2 of Figure 1.

Referring to Figure l, the distributor mechanism is supported within a housing 10. Cam 11 rotates within housing and supplies the driving force to open and close the contact points. The actual contact making and breaking apparatus comprises base 12 which is supported in distributor housing 10 and is secured by fastening means inserted through oblong openings 13. These openings are made oblong to permit adjustment of base 12 with respect to cam 11. This permits the spacing of the contact points to be accurately set.

Base 12 is preferably fabricated as a sheet metal stamping and is provided with a turned up car 15 upon which is mounted stationary contact point 14. Movable contact point 16 is carried by rigid contact carrying arm 17 which is preferably fabricated in the form of a channel to secure adequate rigidity and lightness. Contact carrying arm 17 carries rubbing block 18 which bears directly upon cam 11 and imparts an oscillatory motion to contact carrying arm 17. Contact carrying arm 17 is securely fastened to spring 19 which in turn is secured to ear 20. Ear 20 may also be economically formed by turning up a portion of base 12. Contact carrying arm 17 must be insulated electrically from base 12. This is readily accomplished by insulating spring 19 from ear 20. However, any desired structure may be used as long as contact carrying arm 17 is not in electrical contact with base 12.

A bracket 22 is positioned adjacent the end of movable contact carrying arm 17 which is remote from movable contact point 16. The face of bracket 22 is approximately parallel to the corresponding face of contact carrying arm 17. The face of bracket 22 adjacent contact carrying arm 17 is embossed to receive and confine bearing member 21 which in the preferred form of the invention is a bearing ball. While the embossing which accommodates this bearing member has been shown in the bracket 22 it is to be understood that either the bracket or the contact arm, or both, may be so formed.

Bracket 22 has been shown insulated from car 20. This is necessary if bearing member 21 .comprises any of the usual electrically conductive metals. However, if bearing member 21 be made non-conductive, bracket 22 need then not be insulated from base 12. Any equivalent construction which prevents conduction of electricity from contact carrying arm 17 to base 12 through bearing member 21 is acceptable.

Spring 19 is most economically fabricated from flat stock and to exert a force tending to urge movable contact arm 17 against stationary contact 16, this spring must be assembled bent into an arc convex towards rigid arm 17. This spring 19 tends to rotate contact carrying arm 17 clockwise. This turning moment is resisted by bearing member 21.

The fact that spring 19 is in the form of an arc while the contact points are closed and changes its form to an arc of shorter radius when the contact points open causes a slight but definite longitudinal relative motion between contact carrying arm 17 and bracket 22. The substantially complete elimination of friction between bracket 22 and contact carrying arm 17 by bearing member 21 enables this apparatus to function at higher speeds without increasing the tension in spring 19 and so increasing wear on the rubbing block.

Due to manufacturing irregularities, the working face of rubbing block 18 is not always exactly parallel to the faces of the cam. In the preferred form of the invention which is shown specifically in Figure 2, bearing member 21 takes the form of a single bearing ball. This bearing ball permits torsional fiexure of spring 19 to accommodate such irregularities without concentrating stress on localized areas of rubbing block 18.

I claim as my invention:

1. A distributor mechanism comprising a base plate, a fixed contact supported by the base plate, a bracket and a leaf spring supported by the base plate at a location remote from the fixed contact, said bracket and leaf spring being electrically insulated from the base plate, a rigid contact carrying member supporting a movable contact adjacent one of its ends and secured to the leaf spring at a position remote from the bracket and intermediate the ends of the rigid contact carrying member, a rubbing block secured to the rigid contact carrying member intermediate its ends and a single bearing ball positioned between the bracket and the end of the rigid contact carrying means which is remote from the movable contact, said bearing ball supporting the end of the rigid contact carrying means upon the bracket while permitting free longitudinal movement of the rigid contact carrying member and free torsional fiexure of the leaf spring.

2. A distributor mechanism comprising a base plate, a fixed contact supported by the base plate, a bracket and a leaf spring supported by the base plate at a location remote from the fixed contact, a rigid contact carrying member supporting a movable contact adjacent one of its ends and secured to the leaf spring at a position remote from the bracket and intermediate the ends of the rigid contact carrying member, a rubbing block secured to the rigid contact carrying member intermediate its ends and a single bearing ball positioned between the bracket and the end of the rigid contact carrying means which is remote from the movable contact, said bearing ball supporting the end of the rigid contact carrying means upon the bracket while permitting free longitudinal movement of the rigid contact carrying member and free torsional fiexure of the leaf spring.

References Cited in the file of this patent UNITED STATES PATENTS 1,694,928 Rider Dec. 11, 1928 2,559,568 Hooven July 3, 1951 2,641,660 McKenna June 9, 1953 

